1. Field of the Invention
This invention relates to a mounting assembly for a panel board bus insulation assembly and, more specifically, to a mounting assembly which includes a mounting plate which couples the bus insulation assembly to the mounting assembly without the use of heat staking or mechanical fasteners.
2. Description of the Prior Art
Panel boards are a convenient method for positioning a plurality of circuit breakers between a power source and a load. The panel board includes a plurality of current conducting buses which are generally aligned parallel to each other within the panel board. Circuit breakers are disposed between the buses thereby connecting the line side and the load side buses. The circuit breakers are mounted on, and the buses are mounted in, a mounting assembly. The mounting assembly typically includes a bus insulation assembly and a mounting plate. The bus insulation assembly maintains proper alignment of the buses and provides a plurality of openings where fasteners on the circuit breakers may be passed through to thereby couple the circuit breaker to the bus. The bus insulation assembly generally includes a plurality of pins extending from the back side. The bus insulation assembly and the pins are both made from a dielectric material such as certain plastics. Generally, the mounting plate includes a plurality of openings. The pins on the bus insulation assembly are passed through the mounting plate openings, resulting in the bus insulation assembly being disposed immediately adjacent to the mounting plate with the pins extending beyond the mounting plate. Heat is applied to the exposed ends, thereby melting and deforming the ends so that the pins can not be passed back through the mounting plate openings. Alternatively, the bus insulation assembly can be fixed to the mounting plate with other types of fasteners, such as screws.
These types of mounting assembly have several disadvantages. For example, by applying heat to the mounting pins, the structural integrity of a mounting pin is compromised making the mounting pin more susceptible to breakage. Another disadvantage of this configuration is that the contact point between the mounting plate and the bus insulation assembly is immediately adjacent to the body of the bus insulation assembly. If the panel board assembly is dropped, during shipping for example, the bus insulation assembly would slide relative to the front face of the mounting bracket causing shear loads on the mounting pins. This may cause the pins to shear off in the mounting openings. Use of fasteners adds additional costs to the manufacture of the mounting assembly due to additional components and assembly time.
There is, therefore, a need for a mounting assembly which does not require reheating the bus insulation assembly mounting pins.
There is a further need for a mounting assembly which allows the mounting pins to flex so that the pins will not be damaged should the panel board be dropped.
There is a further need for a mounting assembly which can be assembled in a cost efficient manner.
These needs, and others, are met by the invention which provides a mounting assembly having a bus insulation assembly with extended mounted pins and a mounting plate having depressed conical mounting pin openings.
The bus insulation assembly is made from a dielectric material such as plastic. The bus insulation assembly includes a plurality of channels through which a plurality of electrical busses may be passed. The bus insulation assembly also includes a plurality of extended mounting pins. The metal mounting plate of the present invention includes depressed conical openings which are sized to fit tightly around the bus insulation assembly""s mounting pins. The edge of the mounting plate openings may be sharp. When the mounting pins are inserted through the mounting plate depressed conical openings, the sharp edge of the depressed conical openings engages, or digs into, the dielectric material. This engagement prevents the bus insulation assembly from being easily removed from the mounting plate. Thus, the bus insulation assembly is secured to the mounting plate without heating the mounting pins and without requiring additional fasteners. Because the mounting pins have an extended length and the conical depression ensures that the contact point between the mounting plate and the pin is spaced from the bus insulation assembly, the mounting pins may flex when the bus insulation assembly is subjected to extreme shear loads, for example, an impact load caused by dropping the panel board.